Deniz Yuksel - Structure of an Engineered Single Chain Surrogate Light Chain Variable Domain

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      Publication Details (including relevant citation   information):

      Morstadt, L.; Bohm, A.; Yuksel, D.; Kumar, K.; Stollar, D.B.;   Baleja, J.D. Protein Sci. 2008, 17,   458-465.

      Abstract:

      The surrogate light chain (SLC) is a key regulator of B cell   development in the bone marrow, resulting in mature B cells that   produce antibodies that are capable of interacting with antigens.   The SLC comprises two noncovalently interacting proteins: VpreB   and 14.1. We engineered a construct to represent the complete   immunoglobulin-like domain of the SLC variable domain in a single   protein chain that could be bacterially expressed. In this   construct, the incomplete immunoglobulin domain of VpreB   (residues 1–102) was linked to the J-segment of 14.1 (residues   40–53), which provided one b-strand to complete the V-like domain   (VpreBJ). Because VpreBJ has the interface to VH chains, but   lacks the unique region of 14.1, which is important for SLC   signaling, we predict that a properly folded VpreBJ would have   the potential to act as a dominant negative mutant of the   surrogate light chain. X-ray crystallography of VpreBJ at 2.0 A°   resolution showed that the engineering was successful.With its   two b-pleated sheets, packed face-to-face, the single chain   VpreBJ resembles a mature light chain immunoglobulin V-domain   (VL). The surface that would normally interact with the VH chain   interacts with a crystallographically related VpreBJ molecule.   The presence of dimeric species in solution was verified by   analytical ultracentrifugation. VpreBJ is easily overexpressed in   bacteria, while retaining the native conformation of an   immunoglobulin domain, and thus may serve as an important reagent   for future studies in B-cell development.

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